The present invention relates to elevation and alignment variable gangways which extend and bridge a gap such as between two misaligned platforms.
There are often situations where one must bridge a gap between discontinuous surfaces or platforms using a structural surface, like a gangway, which is sufficient to support cartage or passenger traffic. Gangways are used particularly in cargo or passenger loading between a dock and a boat, a ramp and an aircraft, or a loading platform and a vehicle.
One example is a situation where an access ramp is placed adjacent an airplane cabin access doorway. In order to insert a gangway, the ramp will usually have an exit platform which is adjusted approximately to the same elevation as the sill of the aircraft doorway. Further, the surface must usually be carefully positioned so as to be aligned with the doorway. In many instances, it is only important that the gangway reach the sill of the doorway""s platform. However, the alignment is particularly important when there are fixed hand rails projecting from the doorway""s platform; these rails act to constrain access. In such a case, the gangway must be precisely aligned to pass between the hand rails and reach the doorway""s platform recessed through the rails.
Again in an aircraft context, the boarding and deplaning of disabled persons must be addressed and can be particularly challenging because neither the aircraft nor the boarding device can be accurately positioned. Unlike large commercial aircraft, smaller regional aircraft have aircraft cabin doors which cannot be aligned with the usual boarding tunnels and motorized bridges. Instead, the cabin doors comprise a pivoting door the inside of which is fitted with stairs for boarding and deplaning. When the door is pivoted outwardly from the aircraft fuselage to open the aircraft doorway, the distal end of the door reaches downwardly to the tarmac. The inside of the aircraft door forms a staircase and side hand rails pivot into an upright and supporting position. Certainly, the stairs are difficult to navigate by the mobility-impaired and impossible for accommodating wheelchairs. Further, the cabin door and particularly the side handrails, tend to block many of the usual apparatus adapted to provide elevated access to the aircraft doorway, including wheelchair lifts and inclined ramps. It is difficult to successfully extend outwards to bridge between the platforms while still being able to pass between the narrow, constricting side handrails. It is also important to be able to secure the gangway from slipping from the platform during use.
The difficulties associated with alignment between two, often narrow, passageways are obviated using a fully floating gangway. In one embodiment, the floating gangway is supported in a mobile ramp and comprises a movable frame sandwiched movably in an operating plane between lower and upper parallel bearing surfaces. A bridging element or gangway extends from the frame""s front end for extending to another platform such as an aircraft doorway. Manipulation of the frame forwards, rearwardly, and rotationally enables the gangway to be aligned with the doorway. Further, the gangway can be pivotally connected to the frame so as to enable vertical adjustment of the gangway so to adapt to differential elevations of the proximal and distal ends of the gangway. In the case of aircraft or watercraft, this elevation can also vary during the boarding process. The floating gangway is equally adaptable to structures such as mobile ramps, stationary jet bridges, warehouse loading docks and the like.
In one aspect of the invention, a method for aligning a gangway between a first platform and a second platform is provided comprising the steps of:
supporting a frame between two spaced and parallel bearing surfaces which are positioned below the first platform, the frame being movable in an operating plane parallel to the bearing surfaces;
supporting a proximal end of a gangway from the frame and extending a distal end of the gangway to the second platform; and
manipulating the frame in the operating plane so as to align the supported gangway with the second platform.
Preferably, alignment is further aided by pivoting the proximal end of the gangway from the frame so as to align the elevation of the distal end of the gangway with the second platform. Preferably, in applications associated with the damage critical components of aircraft, it is advantageous to hand manipulate the gangway to minimize risk to the aircraft from insensitive powered movements. To this end, counterbalancing of the gangway about its pivot aids in easing the hand manipulation. Powered assisted manipulation can also be applied. Further, to provide enhanced continuity, one can independently bridge between gangway and the platform using a flap so as to provide a contiguous surface therebetween as the frame is being manipulated. Once manipulated, it is advantageous to lock the gangway to avoid movement in use, such a locking capability being particularly desirable in situations where there is a risk of movement and safety is an issue.
In a broad apparatus aspect, a gangway is supported by a movable frame positioned below a first platform and substantially parallel thereto, the frame having a front end and a rear end and movable at least to translate and rotate in an operating plane, and preferably laterally as well. Preferably, said operating plane is defined by movably supporting and sandwiching the frame between upper and lower bearing surfaces, the lower bearing surface positioned below the frame and parallel to the operating plane and the upper bearing surface positioned spaced above and parallel to the operating plane. A bridge extends forward from the frame""s front end for extending between the frame and the second platform and so that, as the frame moves, the bridge also translates and rotates with respect to the second platform. Preferably, the bridge is pivotally connected at a hinge to the frame and is counterbalanced to make the frame easier to manipulate. A flap between the bridge and first platform forms a contiguous gangway and ensures continuity in all platform traffic situations.
In one embodiment, the frame is movably supported between the upper and lower surfaces by one or more first bearings, preferably laterally spaced swiveling castors, for moveably supporting the front end and one or more second bearings, such as another swiveling castor, positioned rearwardly of the first bearings. Bridge weight loads the front end of the frame and causes the front castors to bear against the lower bearing surface and causes the rear end of the frame to rotate upwardly so that the rear castor bears upwardly against the upper bearing surface.